Policy evaluation for the subsidy for influenza vaccination in elderly

In Japan, the subsidy of influenza vaccination for the elderly was introduced in November 2001. This paper examines its policy evaluation from the viewpoint of cost-benefit analysis.

The data of copayment of influenza vaccination, population and shot rate of the elderly are surveyed by telephone interview to the correspondents in the local governments of Tokyo metropolitan and other 12 big cities in Japan. The mortality due to pneumonia or influenza is obtained from Vital Statistics of Population.

At first, I examine the impact of amount of copayment, through its effect on shot rate, on the percentage of elderly receiving influenza vaccinations. Using these estimation results, benefit-cost ratio (BCR) is calculated.

The estimated coefficient of copayment on shot rate is -0.007 and statistically significant. Shot rate significantly reduces pneumonia and influenza mortality and its magnitude is -0.0028. The obtained net benefit (NB) is 134.9 million yen or US$1.08 billion and benefit-cost ratio is 22.9 and its 95% confidence interval is [2.2, 43.7].

If copayment would be cut by a 1000 yen (US$8), it could avoid about 400 deaths in average big city. The benefit-cost ratio is quite high compared with the other countries or other vaccinations.

We found the strong evidence in a sense of cost-benefit analysis in the subsidy for influenza vaccination in the elderly.